There was a regression introduced by the blamed commit, where pinging to
a VLAN-unaware bridge would fail with the repeated message "Couldn't
decode source port" coming from the tagging protocol driver.
When receiving packets with a bridge_vid as determined by
dsa_tag_8021q_bridge_join(), dsa_8021q_rcv() will decode:
- source_port = 0 (which isn't really valid, more like "don't know")
- switch_id = 0 (which isn't really valid, more like "don't know")
- vbid = value in range 1-7
Since the blamed patch has reversed the order of the checks, we are now
going to believe that source_port != -1 and switch_id != -1, so they're
valid, but they aren't.
The minimal solution to the problem is to only populate source_port and
switch_id with what dsa_8021q_rcv() came up with, if the vbid is zero,
i.e. the source port information is trustworthy.
Fixes: c1ae02d87689 ("net: dsa: tag_sja1105: always prefer source port information from INCL_SRCPT")
Signed-off-by: Vladimir Oltean <[email protected]>
---
net/dsa/tag_sja1105.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/net/dsa/tag_sja1105.c b/net/dsa/tag_sja1105.c
index 796e4b88f63b..f480ffffa8c3 100644
--- a/net/dsa/tag_sja1105.c
+++ b/net/dsa/tag_sja1105.c
@@ -531,11 +531,14 @@ static struct sk_buff *sja1105_rcv(struct sk_buff *skb,
* if available. This allows us to not overwrite a valid source
* port and switch ID with zeroes when receiving link-local
* frames from a VLAN-unaware bridged port (non-zero vbid) or a
- * VLAN-aware bridged port (non-zero vid).
+ * VLAN-aware bridged port (non-zero vid). Furthermore, the
+ * tag_8021q source port information is only of trust when the
+ * vbid is 0 (precise port). Otherwise, tmp_source_port and
+ * tmp_switch_id will be zeroes.
*/
- if (source_port == -1)
+ if (vbid == 0 && source_port == -1)
source_port = tmp_source_port;
- if (switch_id == -1)
+ if (vbid == 0 && switch_id == -1)
switch_id = tmp_switch_id;
} else if (source_port == -1 && switch_id == -1) {
/* Packets with no source information have no chance of
--
2.34.1
On Sat, Jul 01, 2023 at 01:20:10AM +0300, Vladimir Oltean wrote:
> There was a regression introduced by the blamed commit, where pinging to
> a VLAN-unaware bridge would fail with the repeated message "Couldn't
> decode source port" coming from the tagging protocol driver.
>
> When receiving packets with a bridge_vid as determined by
> dsa_tag_8021q_bridge_join(), dsa_8021q_rcv() will decode:
> - source_port = 0 (which isn't really valid, more like "don't know")
> - switch_id = 0 (which isn't really valid, more like "don't know")
> - vbid = value in range 1-7
>
> Since the blamed patch has reversed the order of the checks, we are now
> going to believe that source_port != -1 and switch_id != -1, so they're
> valid, but they aren't.
>
> The minimal solution to the problem is to only populate source_port and
> switch_id with what dsa_8021q_rcv() came up with, if the vbid is zero,
> i.e. the source port information is trustworthy.
>
> Fixes: c1ae02d87689 ("net: dsa: tag_sja1105: always prefer source port information from INCL_SRCPT")
> Signed-off-by: Vladimir Oltean <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Hello:
This patch was applied to netdev/net.git (main)
by David S. Miller <[email protected]>:
On Sat, 1 Jul 2023 01:20:10 +0300 you wrote:
> There was a regression introduced by the blamed commit, where pinging to
> a VLAN-unaware bridge would fail with the repeated message "Couldn't
> decode source port" coming from the tagging protocol driver.
>
> When receiving packets with a bridge_vid as determined by
> dsa_tag_8021q_bridge_join(), dsa_8021q_rcv() will decode:
> - source_port = 0 (which isn't really valid, more like "don't know")
> - switch_id = 0 (which isn't really valid, more like "don't know")
> - vbid = value in range 1-7
>
> [...]
Here is the summary with links:
- [net] net: dsa: tag_sja1105: fix source port decoding in vlan_filtering=0 bridge mode
https://git.kernel.org/netdev/net/c/a398b9ea0c3b
You are awesome, thank you!
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